Technical Field
The present invention relates to the field of touch screen, and particularly to an OGS touch screen substrate, a method of manufacturing a touch screen substrate, a display apparatus including a touch screen, and more particularly to a process of forming a capacitance layer by silver nanowires and of forming bridges by copper.
Description of the Related Art
A touch screen, serving as a smart man-machine interface product, has been applied widely in many applications of daily life and production, particularly in consumer electronics products (such as, smart mobile phone, tablet, etc.).
The touch screen mainly includes resistance type, capacitance type, infrared type and surface acoustic type touch screens. A capacitance type touch screen has advantages of rapid response, multi-touch and long lifetime and thus becomes current main technology in market.
An OGS (One Glass Solution) capacitance touch screen has advantages of more simply in structure, lighter in weight, thinner in thickness and better in light transmittance than a double-glass (G/G) touch screen. Further, as the OGS touch screen may be produced by saving one glass substrate as well as an assembling and bonding procedure, it can be made at reduced cost and increased yield.
Conventional OGS touch screen substrate is structurally shown in FIG. 1. FIG. 1 is a sectional view of the touch screen substrate along a side direction. As shown in FIG. 1, the touch screen substrate includes a cover lens 1 and a light shielding layer 2 formed on the cover lens 1. The light shielding layer 2 on the cover lens 1 is patterned as a rectangle pattern which thus is also termed as black matrix (BM). A flat layer 3 is covered over the cover lens 1 and the light shielding layer 2 such that the cover lens 1 that has been applied the light shielding layer 2 is maintained in flatness. In the OGS touch screen substrate, the flat layer 3 may not be provided, in order for increasing light transmittance and saving procedure cost. Then, a transparent capacitance layer 4 is formed on the flat layer 3, and an over coat layer 5 is covered over the transparent capacitance layer 4. Subsequently, conductive bridges 6 are formed on the first cover layer 5, in which the conductive bridges 6 are connected to the transparent capacitance layer 4 via conductive lines formed in the through holes of the first cover layer 5, thereby enabling the transparent capacitance layers 4 arranged in a direction (for example, in left-right direction as shown in FIG. 1) to be electrically connected. In addition, an electrical connection line 71 is formed at a side face of the first cover layer 5 and the flat layer 2, for connection to a touch detecting circuit.
FIGS. 2A˜2F are side sectional views of the touch screen substrate during a conventional manufacturing process.
Firstly, as shown in FIG. 2A, a light shielding layer 2 is formed on a cover lens 1. The light shielding layer 2 may be formed using printing ink or black metal layer, through a silk screen printing process or through a vacuum magnetron sputtering process.
Then, as shown in FIG. 2B, a flat layer 3 is formed on the cover lens 1 and the light shielding layer 2. The flat layer 3 is made of transparent insulating material, such as SiO2, by, such as, a vacuum magnetron sputtering process.
Followed by, as shown in FIG. 2C, a transparent capacitance layer 4 is formed on the flat layer 3 through a patterning process. For example, the transparent capacitance layer 4 is made of transparent materials, such as ITO material, through patterning processes including steps of coating, exposing, developing, hardening, etching, stripping and the like.
Then, as shown in FIG. 2D, a first cover layer 5 is applied on the flat layer 3, on which a transparent capacitance layer 4 is formed, and through holes 51 are formed in the first cover layer 5 through an etching process so as to connect the transparent capacitance layer 4.
Then, as shown in FIG. 2E, a conductive connection line is formed using ITO material through a second patterning process, such that the conductive bridges 6 bridge two adjacent capacitance electrodes, such as the electrodes extending in a left-right direction. The second patterning process includes steps of coating, exposing, developing, hardening, etching, stripping and the like.
Thereafter, as shown in FIG. 2F, an electrical connection line 71 is formed on a side face of the first cover layer 5 and the flat layer 2. The electrical connection line may be also made of ITO material.
Finally, a second cover layer 8 is formed on the first cover layer 5, obtaining the OGS touch screen substrate as shown in FIG. 1.
It can be seen from the above that, the transparent capacitance layer 4 and the conductive bridges 6 are formed using the ITO thin films through two patterning processes, and each of the patterning processes includes steps of coating, exposing, developing, hardening, etching, stripping and the like. Further, a similar patterning process may be employed to form the electrical connection line 71. Thus, the conventional process of manufacturing a touch screen substrate becomes complex and thus leads to a rather low yield.